Non-Mendelian Genetics Advanced Genetics Non-Mendelian Genetics

Back to Mendel Looked at 7 characteristics of pea plants Came of with the law of Independent Assortment - meaning that the genes assort themselves independently of each other and that one will not effect the other

Why this happens All of the traits he looked at were on separate chromosomes If they would have been located on the same chromosome, he would not have been able to determine this

Linked Traits We know now that some traits are linked together because they are located on the same chromosome Red hair and freckles are linked traits because they are located on the same chromosome Punnett Squares do not work with linked traits

Probability of Rolling Dice Punnett Square

Multiple Genes Some traits have multiple genes that effect one trait Example: Height

For our example lets say there are 6 different genes that effect height. If you have 0 of those genes you’ll be short, if you have all 6 of the genes you’ll be tall *In humans there’s really 13 genes that code for height

Example A man and a woman each have 3 genes so they are both average height They produce offspring, how tall will their kids be? AaBbCc x AaBbCc They each have 3 of the genes that make them tall If it were AABBCC they would be really tall If it were aabbcc they would be really short

ABC ABc AbC Abc aBC aBc abC abc 6 5 4 3 2 1 Height Total Number 1 6 2 15 3 20 4 5

Any time you have a bell shaped curve it is multiple genes that effect that trait Multiple genes affecting a trait is known as polygenic inheritance

Sex Linkage Thomas Hunt Morgan used Mendel’s work to discover this idea using fruit flies There are certain traits that are linked to the sex chromosomes

Sex Linkage in Humans Color blindness is a sex linked trait

Mom’s can be carriers for color blindness Punnett Square

Nonnuclear Inheritance Mitochondria have their own DNA Mitochondria come from the egg, or the mom and are passed on from generation to generation There is no crossing over that occurs in the mitochondria Chloroplasts contain their own DNA in plants